[ServiceWorkerCache Cleanup] Make the state of the cache backend explicit

content/browser/service_worker/service_worker_cache.h

Index: content/browser/service_worker/service_worker_cache.h
diff --git a/content/browser/service_worker/service_worker_cache.h b/content/browser/service_worker/service_worker_cache.h
index 6683797e99236b9a75d07760068ecd1269e3c75c..b443407f91d63a41fbe77d7f3c1ed45a30f2ad19 100644
--- a/content/browser/service_worker/service_worker_cache.h
+++ b/content/browser/service_worker/service_worker_cache.h
@@ -108,6 +108,15 @@ class CONTENT_EXPORT ServiceWorkerCache
   class BlobReader;
   struct KeysContext;
   struct PutContext;
+
+  // The backend progresses from uninitialized, to open, to closed, and cannot
+  // reverse direction.  The open step may be skipped.
+  enum BackendState {
+    BackendUninitialized,  // No backend, create backend on first operation.

[falken, 2014/11/07 05:03:21]

Style nit: chromium enums are SNAKE_CASE

[jkarlin, 2014/11/07 18:55:57]

Thanks! Done in https://codereview.chromium.org/692993005/

+    BackendOpen,           // Backend can be used.
+    BackendClosed          // Backend cannot be used.  All ops should fail.
+  };
+
   typedef std::vector<disk_cache::Entry*> Entries;
 
   ServiceWorkerCache(
@@ -148,7 +157,7 @@ class CONTENT_EXPORT ServiceWorkerCache
   // success). The callback will always be called. Virtual for tests.
   virtual void CreateBackend(const ErrorCallback& callback);
 
-  void Init(const base::Closure& callback);
+  void InitBackend(const base::Closure& callback);
   void InitDone(ErrorType error);
 
   void IncPendingOps() { pending_ops_++; }
@@ -171,7 +180,7 @@ class CONTENT_EXPORT ServiceWorkerCache
   net::URLRequestContext* request_context_;
   scoped_refptr<storage::QuotaManagerProxy> quota_manager_proxy_;
   base::WeakPtr<storage::BlobStorageContext> blob_storage_context_;
-  bool initialized_;
+  BackendState backend_state_;
   std::vector<base::Closure> init_callbacks_;
 
   // Whether or not to store data in disk or memory.